//Clone TFS repository. This will take a few hours depending on the size of the repository
git-tf clone http://yourtfsserver:8080/tfs/colletionname $/TeamProjectA/Main --deep
//Navigate to the just created folder
cd TeamProjectA/Main
//Add new remote repository
git remote add origin https://example.visualstudio.com/DefaultCollection/_git/TeamProjectA
//Push all
git push -u origin --all